光纤松耦合型传感器特性研究

本文介绍一种实用的光纤传感器,它由二根光纤或多根光纤紧靠一起,并在同一位置除去局部包层,成为松耦合状态,在这种状态下,研究了它的特性和应用。 当耦合间隙中充满某种液体介质时,耦合效率明显增大,因此可以方便地判别该介质是否存在。并且实验证明了一种光纤只能有一种相近于光纤芯子折射率的介质具有最大的灵敏度。当间隙内的介质不变时,耦合功率的大小决定于耦合距离d和耦合长度l,l一旦决定以后,d的调节精度为0.1mm量级,易于在机械结构上实现线性检测。

RESEARCH ON THE CHARACTERISTICS OF CROSS-TALK FIBER-OPTIC SENSOR

A practical fiber-optic sensor is presented in this paper. When two fibers or more are nearly adjacent over some distance where the cladding being removed, an effect called "cross-talk" can be obtained. A fiber-optic sensor based on this effect is developed.While coulping area is filled with some liquid medium, the coulping efficiency becomes much higher. Therefore, it is convinient to judge whether the medium exist or not. As can be seen from experimental results, a certain fiber only has a certain medium whose index is similiar to that of the core for achieving the largest sensitivity. For a certain medium between the fibers, coulping power depends on coulping interval D and coulping length L, whenever L is fixed, the alignment precision of D is the order of magnitude of 0.1mm. Consequently, it is easy to achieve linear measurement with compact mechanics construction.